Sanofi
…chemicals, and two medical equipment businesses. Aventis was formed in 1999, when the French company Rhône-Poulenc S.A. merged with the German corporation Hoechst Marion Roussel, which itself was formed from the 1995 merger of Hoechst AG with Cassella, Roussel Uclaf, and Marion Merrell Dow. Hoechst AG, the majority partner at…